<?php
/**
 * eGroupWare - Calendar's timezone information
 *
 * Timezone information get imported from SQLite database, "borrowed" of Lighting TB extension.
 *
 * @link http://www.egroupware.org
 * @package calendar
 * @author Ralf Becker <RalfBecker-AT-outdoor-training.de>
 * @copyright (c) 2009 by RalfBecker-At-outdoor-training.de
 * @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
 * @version $Id: class.calendar_timezones.inc.php 36917 2011-10-11 16:13:52Z ralfbecker $
 */

/**
 * Class for timezone information
 *
 * This class serves two purposes:
 * - convert between TZID strings and nummeric tz_id's stored in database
 * - get iCal VTIMEZONE component for a TZID (data from Lighting extension)
 *
 * Recommendations about timezone handling in calendars:
 * @link http://www.calconnect.org/publications/icalendartimezoneproblemsandrecommendationsv1.0.pdf
 *
 * Mapping Windows timezone to standard TZID's:
 * @link http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/windows_tzid.html
 *
 * UTC is treated specially: it's implicitly mapped to tz_id=-1 (to be able to store it for events),
 * but calendar_ical creates NO VTIMEZONE component for it.
 */
class calendar_timezones
{
	/**
	 * Methods callable via menuation
	 *
	 * @var array
	 */
	public $public_functions = array(
		'update' => true,
	);

	/**
	 * Name of timezone table
	 */
	const TABLE = 'egw_cal_timezones';

	/**
	 * Cached timezone data (reference to session created by init_static)
	 *
	 * @var array id => data
	 */
	protected static $tz_cache = array();

	/**
	 * Cached timezone data (reference to session created by init_static)
	 *
	 * @var array tzid => id
	 */
	protected static $tz2id = array();

	/**
	 * Get DateTimeZone object for a given TZID
	 *
	 * We use our database to replace eg. Windows timezones not understood by PHP with their standard TZID
	 *
	 * @param string $tzid
	 * @return DateTimeZone
	 * @throws Exception if called with an unknown TZID
	 */
	public function DateTimeZone($tzid)
	{
		if (($id = self::tz2id($tzid,'alias')))
		{
			$tzid = self::id2tz($id);
		}
		return new DateTimeZone($tzid);
	}

	/**
	 * Get the nummeric id (or other data) for a given TZID
	 *
	 * Examples:
	 * - calendar_timezone::tz2id('Europe/Berlin') returns nummeric id for given TZID
	 * - calendar_timezone::tz2id('Europe/Berlin','component') returns VTIMEZONE component for given TZID
	 *
	 * @param string $tzid TZID
	 * @param string $what='id' what to return, default id, null for whole array
	 * @return int tz_id or null if not found
	 */
	public static function tz2id($tzid,$what='id')
	{
		$id =& self::$tz2id[$tzid];

		if (!isset($id))
		{
			if (($data = $GLOBALS['egw']->db->select(self::TABLE,'*',array(
				'tz_tzid' => $tzid,
			),__LINE__,__FILE__,false,'','calendar')->fetch()))
			{
				$id = $data['tz_id'];
				self::$tz_cache[$id] = egw_db::strip_array_keys($data,'tz_');
			}
		}
		if (isset($id) && $what != 'id')
		{
			return self::id2tz($id,$what);
		}
		return $id;
	}

	/**
	 * Get timezone data for a given nummeric id
	 *
	 * if NOT tzid or alias queried, we automatically resolve an evtl. alias
	 *
	 * Example:
	 * - calendar_timezone::id2tz($id) returns TZID
	 * - calendar_timezone::id2tz($id,'component') returns VTIMEZONE component for the given id
	 *
	 * @param int $id
	 * @param string $what='tzid' what data to return or null for whole data array, with keys 'id', 'tzid', 'component', 'alias', 'latitude', 'longitude'
	 * @return mixed false: if not found
	 */
	public static function id2tz($id,$what='tzid')
	{
		$data =& self::$tz_cache[$id];

		if (!isset($data))
		{
			if (($data = $GLOBALS['egw']->db->select(self::TABLE,'*',array(
				'tz_id' => $id,
			),__LINE__,__FILE__,false,'','calendar')->fetch()))
			{
				$data = egw_db::strip_array_keys($data,'tz_');
				self::$tz2id[$data['tzid']] = $id;
			}
		}
		// if not tzid queried, resolve aliases automatically
		if ($data && $data['alias'] && $what != 'tzid' && $what != 'alias')
		{
			$data = self::id2tz($data['alias'],null);
		}
		return !$data ? $data : ($what ? $data[$what] : $data);
	}

	/**
	 * Init static variables for session and check for updated timezone information
	 *
	 * As we use returned references from the session, we do NOT need to care about storing the information explicitly
	 */
	public static function init_static()
	{
		self::$tz_cache =& egw_cache::getSession(__CLASS__,'tz_cache');
		self::$tz2id =& egw_cache::getSession(__CLASS__,'tz2id');

		// init cache with mapping UTC <--> -1, as UTC is no real timezone, but we need to be able to use it in calendar
		if (!is_array(self::$tz2id))
		{
			self::$tz_cache = array('-1' => array(
				'tzid' => 'UTC',
				'id' => -1,
			));
			self::$tz2id = array('UTC' => -1);
		}

		// check for updated timezones once per session
		if (!egw_cache::getSession(__CLASS__, 'tzs_checked'))
		{
			try
			{
				$msg = self::import_sqlite($updated);
				if ($updated) error_log($msg);	// log that timezones have been updated
				$msg = self::import_tz_aliases($updated);
				if ($updated) error_log($msg);	// log that timezone aliases have been updated
			}
			catch (Exception $e)
			{
				_egw_log_exception($e);	// log the exception to error_log, but do not stall program execution
			}
			egw_cache::setSession(__CLASS__, 'tzs_checked', true);
		}
	}

	/**
	 * Import timezones from sqlite file
	 *
	 * @param boolean &$updated=null on return true if update was neccessary, false if tz's were already up to date
	 * @param string $file='calendar/setup/timezones.sqlite' filename relative to EGW_SERVER_ROOT
	 * @param boolean $check_version=true true: check version and only act, if it's different
	 * @return string message about update
	 * @throws egw_exception_wrong_parameter if $file is not readable or wrong format/version
	 * @throws egw_exception_assertion_failed if no PDO sqlite support
	 * @throws egw_exception_wrong_userinput for broken sqlite extension
	 */
	public static function import_sqlite(&$updated=null,$file='calendar/setup/timezones.sqlite',$check_version=true)
	{
		$path = EGW_SERVER_ROOT.'/'.$file;

		if (!file_exists($path) || !is_readable($path))
		{
			throw new egw_exception_wrong_parameter(__METHOD__."('$file') not found or readable!");
		}
		if (!check_load_extension('pdo') || !check_load_extension('pdo_sqlite'))
		{
			throw new egw_exception_assertion_failed(__METHOD__."('$file') required SQLite support (PHP extension pdo_sqlite) missing!");
		}
		$pdo = new PDO('sqlite:'.$path);
		// some PHP pdo_sqlite can for whatever reason NOT read the timezones database (reported eg. on Gentu)
		// not much we can do, but give an good error message, with a download link to the MySQL dump
		if (!($rs = $pdo->query('SELECT version FROM tz_schema_version')))
		{
			throw new egw_exception_wrong_userinput(
				lang('Your PHP extension pdo_sqlite is broken!').'<br />'.lang('It can NOT read timezones from sqlite database %1!',$path).'<br />'.
				lang('As an alternative you can %1download a MySQL dump%2 and import it manually into egw_cal_timezones table.',
					'<a href="http://dev.egroupware.org/other/egw_cal_timezones.sql.bz2">','</a>'));
		}
		if ($rs->fetchColumn() != 1)
		{
			throw new egw_exception_wrong_parameter(__METHOD__."('$file') only schema version 1 supported!");
		}
		$tz_version = $pdo->query('SELECT version FROM tz_version')->fetchColumn();
		$config = config::read('phpgwapi');
		//echo "<p>tz_version($path)=$tz_version, tz_db_version=$config[tz_version]</p>\n";
		if ($tz_version === $config['tz_version'])
		{
			$updated = false;
			return lang('Nothing to update, version is already %1.',$config['tz_version']);	// we already have the right
		}
		$tz2id = array();
		foreach($pdo->query('SELECT * FROM tz_data ORDER BY alias') as $data)
		{
			if ($data['alias'])
			{
				$data['alias'] = $tz2id[$data['alias']];
				if (!$data['alias']) continue;	// there's no such tzid
			}
			// check if already in database
			$tz2id[$data['tzid']] = $GLOBALS['egw']->db->select('egw_cal_timezones','tz_id',array(
					'tz_tzid' => $data['tzid'],
				),__LINE__,__FILE__,false,'','calendar')->fetchColumn();

			$GLOBALS['egw']->db->insert('egw_cal_timezones',array(
				'tz_alias' => $data['alias'],
				'tz_latitude' => $data['latitude'],
				'tz_longitude' => $data['longitude'],
				'tz_component' => $data['component'],
			),array(
				'tz_tzid' => $data['tzid'],
			),__LINE__,__FILE__,'calendar');

			// only query last insert id, if not already in database (gives warning for PostgreSQL)
			if (!$tz2id[$data['tzid']]) $tz2id[$data['tzid']] = $GLOBALS['egw']->db->get_last_insert_id('egw_cal_timezones','tz_id');
		}
		config::save_value('tz_version', $tz_version, 'phpgwapi');

		//_debug_array($tz2id);
		$updated = true;
		return lang('Timezones updated to version %1 (%2 records updated).',$tz_version,count($tz2id));
	}

	/**
	 * Import timezone aliases
	 *
	 * @param boolean &$updated=null on return true if update was neccessary, false if tz's were already up to date
	 * @param string $file='calendar/setup/tz_aliases.inc.php' filename relative to EGW_SERVER_ROOT
	 * @param boolean $check_mtime=true true: check version and only act, if it's different
	 * @return string message about update
	 * @throws egw_exception_wrong_parameter if $file is not readable or wrong format/version
	 */
	public static function import_tz_aliases(&$updated=null,$file='calendar/setup/tz_aliases.inc.php',$check_mtime=true)
	{
		$path = EGW_SERVER_ROOT.'/'.$file;

		if (!file_exists($path) || !is_readable($path))
		{
			throw new egw_exception_wrong_parameter(__METHOD__."('$file') not found or readable!");
		}
		$config = config::read('phpgwapi');
		$tz_aliases_mtime = date('Y-m-d H:i:s', filemtime($path));
		if ($tz_aliases_mtime === $config['tz_aliases_mtime'])
		{
			$updated = false;
			return lang('Nothing to update, version is already %1.',$tz_aliases_mtime);
		}
		include($path);	// sets $tz_aliases

		$updates = 0;
		foreach($tz_aliases as $alias => $tzid)
		{
			if ((!($alias_id=self::tz2id($alias, 'alias')) || self::id2tz($alias_id, 'tzid') !== $tzid) &&	// not in DB or different
				($tz_id = self::tz2id($tzid)))	// given tzid for alias exists in DB
			{
				$GLOBALS['egw']->db->insert('egw_cal_timezones',array(
					'tz_alias' => $tz_id,
				),array(
					'tz_tzid' => $alias,
				),__LINE__,__FILE__,'calendar');
				++$updates;
			}
			//error_log(__METHOD__."() alias=$alias, tzid=$tzid --> self::tz2id('$alias', 'alias') = ".array2string($alias_id).",  self::tz2id('$tzid')=".array2string($tz_id));
		}
		config::save_value('tz_aliases_mtime',$tz_aliases_mtime,$app='phpgwapi');

		//_debug_array($tz2id);
		$updated = true;
		return lang('Timezones aliases updated to version %1 (%2 records updated).', $tz_aliases_mtime, $updates);
	}

	/**
	 * Admin >> Update timezones
	 *
	 */
	public function update()
	{
		if (!$GLOBALS['egw_info']['user']['apps']['admin'])
		{
			throw new egw_exception_no_permission_admin();
		}
		$GLOBALS['egw']->framework->render(
			'<h3>'.self::import_sqlite()."</h3>\n".
			'<h3>'.self::import_tz_aliases()."</h3>\n",
			lang('Update timezones'),true);
	}
}
/*
if (isset($_SERVER['SCRIPT_FILENAME']) && $_SERVER['SCRIPT_FILENAME'] == __FILE__)	// some tests
{
	$GLOBALS['egw_info'] = array(
		'flags' => array(
			'currentapp' => 'calendar',
		)
	);
	include('../../header.inc.php');
	calendar_timezones::init_static();

//	echo "<h3>Testing availability of VTIMEZONE data for each tzid supported by PHP</h3>\n";
//	foreach(DateTimeZone::listIdentifiers() as $tz)
	echo "<h3>Testing availability of VTIMEZONE data for each TZID supported by EGroupware</h3>\n";
	foreach(call_user_func_array('array_merge',egw_time::getTimezones()) as $tz => $label)
	{
		if (($id = calendar_timezones::tz2id($tz,'component')) || $tz == 'UTC')	// UTC is always supported
		{
			$found[] = $tz;
			//if (substr($tz,0,10) == 'Australia/') echo "$tz: found<br />\n";
		}
		else
		{
			$not_found[] = $tz;
			echo "$tz: <b>NOT</b> found<br />\n";
		}
	}
	echo '<h3>'.count($found).' found, '.count($not_found)." <b>NOT</b> found</h3>\n";

	if ($not_found) echo "<pre>\n\$no_vtimezone = array(\n\t'".implode("',\n\t'",$not_found)."',\n);\n</pre>\n";

	echo "<h3>Testing availability of PHP support for each TZID supported by EGroupware's timezone database:</h3>\n";
	foreach($GLOBALS['egw']->db->select('egw_cal_timezones','*',false,__LINE__,__FILE__,false,'','calendar') as $row)
	{
		try
		{
			$timezone = new DateTimeZone($row['tz_tzid']);
			//$timezone = calendar_timezones::DateTimeZone($row['tz_tzid']);
			echo $row['tz_tzid'].": available<br />\n";
		}
		catch(Exception $e)
		{
			if (($id = calendar_timezones::tz2id($row['tz_tzid'],'alias')) &&
				($alias = calendar_timezones::id2tz($id)))
			{

				try
				{
					$timezone = new DateTimeZone($alias);
					echo $row['tz_tzid']."='$alias': available through <b>alias</b><br />\n";
					unset($e);
				}
				catch(Exception $e)
				{
					// ignore
				}
			}
			if (isset($e)) echo $row['tz_tzid'].": <b>NOT</b> available<br />\n";
		}
	}
}
else*/
calendar_timezones::init_static();
